This invention relates to surround-sound systems and more particularly to a compact array of microphones and signal-combining circuitry especially suited for furnishing signals intended for use with my invention described in co-pending application Ser. No. 018,967 entitled, "Compatible Four-Channel Radio Broadcast and Receiving System". The present invention is an improvement over my previous inventions in the U.S. Pat. Nos. 4,072,821 and 4,096,353. These patents describe embodiments of my invention capable of producing two-channel SQ coded signals corresponding to directional sounds impinging upon the microphone arrays from various directions around the compass. These coded signals can be decoded using the decoders described in the co-pending application in the 4-2-4 mode. The present application teaches how to generate a new function T in the microphone systems described in the aforementioned patents in order to enable the transmission and decoding of the directional signals to take place in the 4-3-4 or the .theta.-3-4 modes, as hereinafter explained.